• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.398-404
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• 2021

This paper proposes a method of using a magnetic position sensor to detect accurately the rotor position required to perform vector control of a permanent-magnet synchronous motor, particularly the initial rotor position at startup. In the existing vector control systems, the initial rotor position was determined using the output signals of the Hall sensors, or the control was performed in a sensorless method without using such a sensor. On the other hand, the accuracy is degraded due to the occurrence of a position detection error, and the practicality was not satisfactory. This paper attempts to detect the initial rotor position using a magnetic position sensor to solve this problem. This method is used to solve the deteriorating starting characteristics of the motor in the vector control system. In addition, to lower the price of a low-power vector control inverter, this paper proposes a method of integrating the existing sensors and reducing the price to less than half using a magnetic position sensor for speed and position detection.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.30 no.2
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• pp.97-108
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• 1994

The DC Servo Motor has been used as an actuator in automatic control fields because of the good response and the control easiness nevertheless it has some disadvantage such as spark at the brush. Recently, along with the fast development of semiconductor industries, the digital control scheme is increasing in comparison with analog control because of the strength against noise and the accuracy. In this paper, authors proposed a combined control algorithm, which is mixed Modified Minimum Time Position Control(MMTPC) and PI control algorithm. for minimum time position control of DC Servo Motor by the one-chip microcontroller. The proposed control algorithm showed the fast response and offset-free. The validity of the proposed method comparing with the VSS control is proved by the response experiments.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.355-365
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• 1998

The purpose of this study is to evaluate the accuracy of four elastomeric interocclusal recording materials and the weight change according to different storage period (24 hours, 48hours, 7days) and different conditions (dry, wet). The techniques for establishing the intercuspal position were centic occlusion interocclusal record with four elastomeric interocclusal recording materials (Ramitec, Stat-BR, Blu-Mousse, Regisil) (experimental groups) and location of the cast in a position of maximum in-terdigitation using tactile and visual method(control group). To evaluate the accuracy of four elastomeric interocclusal recording materials, the quality of contacts between the mounted casts was compared with the results of an occlusal examination of the same subjects. The results were as follows : 1. The most accurate method of articulating study casts at the intercuspal position was by hand articulation and no significant differences in accuracy were observerd among the experimental groups. 2. In case of interocclusal records storaged in dry sealed plastic box, no significant differences in accuracy were observed among the experimental groups. 3. In case of interocclusal records storaged in water, there was significant inaccuracy in Ramitec group. 4. The biggest weight change was observed in Ramitec group in all storage conditions

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.16-22
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• 2009

This paper deals with the issue of robust position tracking control and energy-saving control for a valve-controlled cylinder system using speed-controlled fixed displacement pump. The whole feedback control system is composed of a pair of interconnected subsystems, that is, valve-controlled cylinder system and load-sensing control system. From experiments it is shown that position tracking control in the load sensing control system can accomplish significant reduction in input energy to pump comparing to a conventional valve-controlled cylinder system, while exhibiting the same position tracking control accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.672-675
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• 1994

This paper presents a new algorithm to determine the receiver position in satellite navigation for GPS(Global Positioning System). The algorithm which based on vector analysis is able to obtain simultaneously the receiver position and the direction vector which is from the receiver position to a satellite. In its first calculation stage it, does riot require the complex initial value which is used in the previous works and affects the accuracy of the observed receiver position. Furthermore, the algorithm tells us whether a selected configuration among the visible satellites is good or poor for the accuracy. Comparing the algorithm with the previous method, the effectiveness of the algorithm is verified through the experimental simulations.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.159-165
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• 1999

Based on the cable-extension transducers, a new technique for two dimensional position measurement is developed in this paper. This new technique includes the use of two such transducers and the planar position is determined through triangulation. This paper also presents uncertainty analysis results for establishing sensor design specifications. An actual prototyped sensor system is built and its accuracy is verified through h\both experiments with coordinate measurement machines and its application to the real-time control of a high load wheeled mobile robot. This new type of position sensor can be easily used in a wide variety of automation applications in industry for two dimensional position measurements with high accuracy over a relatively large range, and it is both cast effective and robust against hostile environments.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.177-180
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• 2010

In cadastral field GPS mainly applies to fundamental survey, while there are numerous research about cadastral detail survey using GPS application in order to increase surveying efficiency as survey technology improve. The purpose of this experiment is to analyze the accuracy of position and estimate the efficiency of GPS/GLONASS combination surveying with control points. As the result of this experiment, Network RTK-GPS/GLONASS combination survey is superior to Newtork RTK-GPS with respect to position accuracy and work efficiency.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.13-20
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• 2010

Currently, NGII(National Geographic Information Institute) provides VRS(Virtual Reference System) service using 44 CORS(Continuously Operating Reference Stations). Since the VRS provides high-precision coordinate in a short time, the users and applications are expected to be rapidly increasing. The accuracy analysis on the VRS service, however, was not sufficiently performed yet. Therefore, in this study, the VRS data is acquired from various circumstances and its accuracy is analyzed. According to analysis, it was concluded that the VRS could be applied to public control point survey. Furthermore, it was found that the PQ(Position Quality) which represents variance of estimated coordinates rather than GDOP(Geometric Dilution of Precision) is more relevant as a factor to determine the accuracy of coordinates. Based on the analysis of data from four manufacturers (TRIMBLE, MAGELLAN, LECIA, TOPCON), it was confirmed that the standard deviations better than 3cm. Therefore, VRS Survey apply to public control point survey.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.949-955
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• 2007

This paper proposes an efficient localization algorithm in the RFID sensor space for the precise localization of a mobile robot. The RFID sensor space consists of embedded sensors and a mobile robot. The embedded sensors, that is tags are holding the absolute position data and provide them to the robot which carries a reader and requests the absolute position fur localization. The reader, it is called as antenna usually, gets several tag data at the same time within its readable range. It takes time to read all the tags and to process the data to estimate the position, which is a major factor to deteriorate the localization accuracy. In this paper, an efficient algorithm to estimate the position and orientation of the mobile robot as quickly as possible has been proposed. Along with the algorithm, a new allocation of the tags in the RFID sensor space is also proposed to improve the localization accuracy. The proposed algorithms are demonstrated and verified through the real experiments.

• Journal of Mechanical Science and Technology
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• v.16 no.6
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• pp.762-769
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• 2002

This paper presents how effective it is to use many features for improving the speed and accuracy of visual servo systems. Some rank conditions which relate the image Jacobian to the control performance are derived. The focus is to describe that the accuracy of the camera position control in the world coordinate system is increased by utilizing redundant features in this paper. It is also proven that the accuracy is improved by increasing the number of features involved. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm robot manipulator made by Samsung Electronic Co. Ltd..